Class ArrayHashMap<K,V>

An Array-based hashtable which maps, similar to Java's HashMap, only
performance tests showed it performs better.

The hashtable is constructed with a given capacity, or 16 as a default. In
case there's not enough room for new pairs, the hashtable grows. Capacity is
adjusted to a power of 2, and there are 2 * capacity entries for the hash.
The pre allocated arrays (for keys, values) are at length of capacity + 1,
where index 0 is used as 'Ground' or 'NULL'.

The arrays are allocated ahead of hash operations, and form an 'empty space'
list, to which the <key,value> pair is allocated.

WARNING: This API is experimental and might change in incompatible ways in the next release.